A power combining circuit for a multi-channel high-frequency power supply

Abstract

The application discloses a power synthesis circuit of a multi-path high-frequency power supply, which synthesizes n paths of input power through n groups of first-stage CV / CC networks and one group of second-stage CC / CV networks; specifically, when designing the two-stage CV / CC and CC / CV networks, the load impedance can be linearly changed to the equivalent input impedance of each power supply according to actual requirements, and the transformation can ensure that the power supply with high sensitivity to the load can also be power synthesized, thus, the power supply has good flexibility and can meet the power supply requirements under a high-frequency circuit.

Description

Technical Field

[0001] This invention belongs to the field of power combining technology, and more specifically, relates to a power combining circuit for multiple high-frequency power supplies. Background Technology

[0002] Currently, the output capacity of a single power supply is limited, making it difficult to meet demand under certain conditions. For example, the output of commonly used high-frequency power inverters is limited by the voltage and current withstand capabilities of the switching devices, resulting in low output power for a single inverter. Therefore, higher output power is usually achieved by combining multiple power sources.

[0003] Currently, power combining still faces the following problems: 1. Coupling exists between the operating states of each power source after the power combining network; 2. Equivalent load impedance changes; 3. The design method is complex and lacks versatility. Taking high-frequency power inverters as an example, because high-frequency inverters are sensitive to load changes, existing designs often use fixed load impedances or complex phase control. However, actual application loads are often flexible and variable, and the state after passing through the power combining network becomes even more complex, limiting its application in high-power power sources. Therefore, when designing a power combining network, impedance compression should usually be considered to bring it as close as possible to the inverter's optimal load point, avoiding hard switching that could cause losses, heat generation, or even damage to components. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a power combining circuit for multiple high-frequency power supplies. The power combining circuit is designed through a two-stage passive two-port network to achieve linear impedance transformation and power combining functions.

[0005] To achieve the above-mentioned objective, the present invention provides a power combining circuit for multiple high-frequency power supplies, characterized in that it includes: multiple input power supplies V1 to V2. n First-stage constant voltage / constant current two-port network and second-stage constant voltage / constant current two-port network;

[0006] The multi-input power supply includes n input voltages, where n is a positive integer greater than 2, which are used to power the first-stage constant voltage / constant current two-port network.

[0007] The first-stage constant voltage / constant current two-port network comprises n groups, which are connected in parallel. Each group is connected in series with a voltage source to convert the n input voltages into n currents, which are then connected in parallel on the output side and connected to the input side of the second-stage constant current / constant voltage two-port network.

[0008] The second-stage constant current / constant voltage two-port network is used to convert the n-channel output current of the first-stage constant voltage / constant current two-port network into a single-channel voltage output, thus obtaining the output of the power combining circuit.

[0009] The objective of this invention is achieved as follows:

[0010] This invention discloses a power combining circuit for multiple high-frequency power supplies. It combines the power of n input power supplies through n first-stage CV / CC networks and one second-stage CC / CV network. Specifically, when designing the two-stage CV / CC and CC / CV networks, the load impedance can be linearly varied to the equivalent input impedance of each power supply according to actual requirements. This transformation can ensure that power supplies with high load sensitivity can also be combined, thus providing good flexibility and adapting to the power supply requirements of high-frequency circuits.

[0011] Meanwhile, the power combining circuit of the multi-channel high-frequency power supply of the present invention also has the following beneficial effects:

[0012] (1) By using CV / CC and CC / CV networks, power synthesis of multiple power supplies was realized, breaking through the current situation of limited output of single high-frequency power supply.

[0013] (2) The power combining network uses CV / CC and CC / CV networks, which are more flexible than the combining network similar to the Chireix synthesizer used by Liu M et al. of Princeton University. The two-stage CV / CC and CC / CV networks are not affected by the load, and the output voltage is linearly related to the input voltage, making them more flexible in practical high-frequency applications.

[0014] (3) CV / CC and CC / CV networks can also perform linear transformation of impedance while power combining. Compared with the power combining network designed by Surakitbovorn K et al. of Stanford University, the equivalent impedance of the power supply can be clearly given. When designing load-sensitive power supplies, it can be well matched to the load range where the power supply is working normally, and the practical application range is wider. Attached Figure Description

[0015] Figure 1 This is a power combining circuit architecture diagram of a multi-channel high-frequency power supply according to the present invention;

[0016] Figure 2 These are three structural diagrams of CV / CC and CC / CV networks;

[0017] Figure 3 This is a simulation model diagram of LTspice for four-channel power combining;

[0018] Figure 4 This is a simulated waveform under ideal conditions;

[0019] Figure 5 These are simulated waveforms for Class-E input voltages of 9.5V, 10V, 10.5V, and 20V, respectively.

[0020] Figure 6 These are simulated waveforms of Class-E output phases of -5°, 0°, 5°, and 10°.

[0021] Figure 7 This is a simulation result diagram when the network capacitance is increased by 10%;

[0022] Figure 8 This is a simulation result diagram when the network capacitance is -10%. Detailed Implementation

[0023] The specific embodiments of the present invention will now be described with reference to the accompanying drawings to enable those skilled in the art to better understand the invention. It should be particularly noted that in the following description, detailed descriptions of known functions and designs that might obscure the main content of the invention will be omitted here.

[0024] Example

[0025] Figure 1 This is a power combining circuit architecture diagram of a multi-channel high-frequency power supply according to the present invention.

[0026] In this embodiment, as Figure 1 As shown, the present invention discloses a power combining circuit for multiple high-frequency power supplies, comprising: multiple input power supplies V1 to V2. n First-stage constant voltage / constant current (CV / CC) two-port network and second-stage constant current / constant voltage (CC / CV) two-port network;

[0027] In this embodiment, the number of first-stage CV / CC two-port networks is determined by the number of power supplies, and the number of second-stage CC / CV two-port networks is 1. The first-stage CV / CC two-port networks are connected in parallel and then connected to the second-stage CC / CV two-port networks for power combining.

[0028] The multi-input power supply contains n input voltages, where n is a positive integer greater than 2, which are used to power the first-stage constant voltage / constant current two-port network.

[0029] The first-stage constant voltage / constant current two-port network consists of n groups, which are connected in parallel. Each group is connected in series with a voltage source to convert the n input voltages into n currents, which are then connected in parallel at the output and fed into the input side of the second-stage constant current / constant voltage two-port network.

[0030] The second-stage constant current / constant voltage two-port network is used to convert the n-channel output current of the first-stage constant voltage / constant current two-port network into a single-channel voltage output, thus obtaining the output of the power combining circuit.

[0031] In this embodiment, both the first-stage constant voltage / constant current two-port network and the second-stage constant current / constant voltage two-port network are passive lossless two-port networks composed of inductors and capacitors, including three network structures: L-type, T-type, and Π-type. However, the input and output port positions of the three network structures of the second-stage constant current / constant voltage two-port network are swapped with those of the three network structures of the first-stage constant voltage / constant current two-port network.

[0032] In this embodiment, the three network structures, L-shaped, T-shaped, and Π-shaped, are as follows: Figure 2 As shown, where, Figure 2 (a) is an L-shaped network structure. Figure 2 (b) is a T-type network structure. Figure 2 (c) is a Π-type network structure;

[0033] In all three network structure diagrams, X represents reactance, which is composed of capacitor, inductor, or a combination of both. Generally, reactances connected in series are inductors or are inductive, while reactances connected in parallel are capacitors or are capacitive.

[0034] Let the transmission matrix of the L-shaped network structure be:

[0035]

[0036] Let the transmission matrix of the T-type network structure be:

[0037]

[0038] Let the transmission matrix of the Π-type network structure be...

[0039]

[0040] In the formula, X1, X2, and X3 all represent reactance.

[0041] If the transmission matrix of all three structures is represented by A, then the voltage-current relationship between the two ports is:

[0042]

[0043] In the formula, a, b, c, and d are the transmission parameters of the two-port network, and their specific values ​​are determined by the structure of the two-port network.

[0044] The load impedance connected to the output port of a two-port network is called the output impedance Z0. The impedance seen through the two-port network at this point is called the input impedance Z0. i The relationship between them is: If a = 0, then the output current... Only with input voltage It is related to the load but independent of other factors, therefore it is called a load-independent constant voltage / constant current (CC / CV) network, where the input voltage is... and output current The relationship is:

[0045]

[0046] For the three types of passive lossless two-port networks, taking Figure 2 Taking the L-shaped network shown in (a) as an example This is the input port; connect the power supply. This is the output port, connecting to the next level network. When X1 = -X2 = X p In this case, the output current flowing through the L-type network depends only on the input voltage, hence it is called a constant voltage / constant current (CV / CC) network; while Figure 2 (b) The T-shaped network shown must satisfy X1=-X3=X p , Figure 2 (c) The Π-shaped network shown in (c) must satisfy X2 = -X3 = -X p All three structures can form a CV / CC network, with the corresponding transmission parameter matrix A. p for:

[0047]

[0048] Where, d p It is determined by the network structure and parameters.

[0049] The specific parameters of the CV / CC network are shown in Table 1.

[0050] Network Structure Type Composition Conditions <![CDATA[d p ]]> L-shaped <![CDATA[X1=-X2=X p ]]> <![CDATA[d p =1]]> T-shaped <![CDATA[X1=-X3=X p ]]> <![CDATA[d p =1-X2 / X p ]]> Π type <![CDATA[X2=-X3=-X p ]]> <![CDATA[d p =1+X p / X1]]>

[0051] Table 1

[0052] A passive, lossless two-port network satisfies the reciprocity theorem: when the input and output ports are interchanged, if the element d = 0 in the second row and second column of the transmission parameter matrix, then its output voltage... Only with input current The relevant relationship is as follows:

[0053]

[0054] This is called a CC / CV network. For the three network structures of CC / CV networks, the L-shaped network must satisfy X1 = -X2 = X. s A T-type network must satisfy X2 = -X3 = X s A Π-type network must satisfy X1 = -X3 = -X s Both can form CV / CC networks, with the corresponding transmission parameter matrix A. s for:

[0055]

[0056] Where a s It is determined by the network structure and parameters.

[0057] The specific parameters of the CV / CC network are shown in Table 2.

[0058]

[0059]

[0060] Table 2

[0061] In summary, the power combining circuit of this invention supplies power to the load through parallel connections of identical CV / CC networks and then through a CC / CV network. Assuming that the amplitude and phase difference of the output voltages of each power source are sufficiently small, the output voltages of each power source can be considered to be identical, and the output current of each inverter through the CV / CC network is also identical. Therefore, the total output current after parallel connection is Furthermore, this current is independent of the impedance of the subsequent stage. After parallel connection, the current flows through the CC / CV network, and the voltage obtained by the load is... Similarly, it is independent of the load, but depends on the power combining network parameters and the input voltage.

[0062] Furthermore, the power combining circuit provided by this invention can perform a linear transformation on the load network. From the impedance relationship of the two-port network, the equivalent impedance seen by the single power supply after power combining can be obtained as follows:

[0063]

[0064] The imaginary part na in the denominator s X s +d p X p =0 satisfies the linear change from load impedance to power supply equivalent impedance, and the changed single-channel power supply equivalent input impedance Load impedance Z L Equivalent impedance Z of a single power supply eq The ratio is called the impedance scaling factor, and is denoted as Z. eq / Z L =λ. The linear load transfer relationship provides a simple method to transfer the actual load impedance region to the target load region. Designers can directly represent the impedance region before and after the transformation by the power combining network in the load impedance plane. This is beneficial for controlling some power supplies that are highly sensitive to loads to ensure normal output.

[0065] Figure 3 The simulation model diagram of LTspice for four-channel power combining.

[0066] The input power supply uses a high-frequency inverter (including but not limited to Class D, Class E, ...). (etc.), its input DC voltage is 10V, and the power combining network adopts a Π-Π type equal impedance combining network. The number of combining channels is designed to be 4, therefore |X p / X s |=2, and to achieve better high-frequency filtering, the series reactance X3 of the two Π-type networks is taken as an inductance, i.e., X p and X s All are positive values. Let X... s If we take it as 20Ω, then X p With an impedance of 40Ω and an operating frequency of 13.56MHz, the corresponding inductances for the CV / CC and CC / CV networks are 469.5nH and 234.7nH, respectively, and the capacitances are 293.4pF and 586.9pF, respectively. Simulations were performed to account for deviations in the output voltage, phase, and network parameters of each Class-E channel under ideal conditions. Figure 4 This is a simulated waveform under ideal conditions. Figure 5 These are simulated waveforms for Class-E input voltages of 9.5V, 10V, 10.5V, and 20V, respectively. Figure 6 These are simulated waveforms of Class-E output with phases of -5°, 0°, 5°, and 10°. Figure 7 These are simulation results when the network capacitance is increased by 10%. Figure 8 These are simulation results with a network capacitance value of -10%. The simulation results show that the inverter can operate normally after being synthesized by the Π-Π type equal-impedance power combining network, and the operating states of each Class-E power supply are completely identical, demonstrating the equal-impedance nature of the power combining network. Furthermore, although the operating states of different Class-E power supplies vary greatly, the synthesized current waveforms are essentially the same. This result indicates that slight imbalances between inverters (including DC voltage amplitude and drive signal phase) have a relatively small impact on the operating states of each inverter, allowing them to maintain the expected zero-voltage switching (ZVS) operation. Finally, the impact of network parameter deviations is also relatively small. However, under certain loads close to the edge of the ZVS load region, it may shift the inverter to the outside of the boundary, causing it to be in a slightly hard-switching state under these loads. Therefore, when designing power combining circuits for power supplies with high load sensitivity (such as inverters), a certain margin should be left between the load region where the power supply operates normally and the target operating region. Simultaneously, it should be ensured that the network parameters do not have large deviations, and the resonant relationship between the reactances of different network properties should be maintained to minimize the impact of parameter deviations.

[0067] Although the illustrative specific embodiments of the present invention have been described above to enable those skilled in the art to understand the invention, it should be understood that the invention is not limited to the scope of the specific embodiments. For those skilled in the art, various changes are obvious as long as they are within the spirit and scope of the invention as defined and determined by the appended claims, and all inventions utilizing the concept of the present invention are protected.

Claims

1. A power combining circuit for multiple high-frequency power supplies, characterized in that, include: Multi-input power supply V1~V n First-stage constant voltage / constant current two-port network and second-stage constant voltage / constant current two-port network; The multi-input power supply includes n input voltages, where n is a positive integer greater than 2, which are used to power the first-stage constant voltage / constant current two-port network. The first-stage constant voltage / constant current two-port network includes n groups, which are connected in parallel. Each group is connected in series with a voltage source to convert the n input voltages into n currents. These currents are then connected in parallel on the output side and connected to the input side of the second-stage constant current / constant voltage two-port network. The second-stage constant current / constant voltage two-port network is used to convert the n-channel output current of the first-stage constant voltage / constant current two-port network into a single-channel voltage output, thus obtaining the output of the power combining circuit.

2. The power combining circuit for a multi-channel high-frequency power supply according to claim 1, characterized in that: The multiple input power supplies use the same model to ensure that the voltage amplitude and phase of the n input voltages are the same.

3. The power combining circuit for a multi-channel high-frequency power supply according to claim 1, characterized in that: The first-stage constant voltage / constant current two-port network adopts a passive and lossless two-port network composed of inductors and capacitors, including three network structures: L-type, T-type, and Π-type.

4. The power combining circuit for a multi-channel high-frequency power supply according to claim 1, characterized in that: The second-stage constant current / constant voltage two-port network has a similar structure to the first-stage constant voltage / constant current two-port network. It also uses a passive and lossless two-port network composed of inductors and capacitors, including three network structures: L-type, T-type, and Π-type. However, the input and output port positions of the three network structures of the second-stage constant current / constant voltage two-port network are swapped with those of the three network structures of the first-stage constant voltage / constant current two-port network.

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